New RAM HD 1000 lb-ft

ShinerBock wrote:


I said this from the beginning so why do you keep rebutting what I am saying?

Because you keep on quoting emissions this, emissions that, as if I never took it into account.

Actually in the case of 400 hp.... Yes, emissions is the ONLY reason why the ISB will not see 400 hp in a commercial application. You can run about 450-475 hp(390-415 rwhp) heavy loads all day long without running into to higher temps or reducing long term reliability. I have seen it in the tests cells when I worked at Cummins and I have seen it with the many hot shoters that I know who run this power level with hundreds of thousands of miles on their trucks.

Now if you were talking 500 hp(440 rwhp), then I would say yes that these power levels will start to reduce longevity with the stock turbo. You would probably be fine towing moderate loads, but heavy loads will cause temps to get to unsafe levels.

Let's think logical for a moment - if an ISB can be tuned that high, what's the point of Cummins making an ISC, ISL / L9, ISM / ISX13?

If an ISB can make 400hp reliability, at any duty cycle, in any application, the you would see them in city buses instead of ISLs. You'd see them in vocational trucks. In 300 size excavators, dozers, etc.

I know the medium/heavy duty market. I have worked in it for more than two decades. Should I find the video of the Ram engineer stating that the reduced power between the the pickup and cab/chassis trucks is mainly do to emissions certifications than duty cycle

While you find me a video, have a look at this please:

https://www.energypower.com.au/theme/energypowercomau/assets/public/File/Industrial%20engine%20ratings%20guide.pdf

It's from CAT. On page 3, you can see how they have 5 classes of duty cycle, from continuous to very intermittent.

On page 18, using C15 as a random example, you can see it's limited to:

- 440 hp continuous
- 540 hp intermittent
- 595 hp occasional max

This is ALL assuming emissions targets are met. What I really want to hear from the Cummins engineer is: was duty cycle a consideration between pickup and chassis cabs?

I never said this. Where did I say this? In fact, my exact words were "I worked at Cummins and can honestly tell you that while reliability is high on the list, it is not the most important thing, passing emissions is." Meaning that while reliability is high on the list when tuning an engine, it is not the main reasons. Meeting emissions is. You can still increase the power output(to an extent) from factory levels without reducing long term reliability.

That's why I said to me emissions is a given. Therefore other than emissions reliability vs duty cycle is the predominant reason.

Getting back on topic, I stand by what I said - Cummins altered the block, piston, rods, head, and turbo just to gain 15 hp / 70 lb-ft RELIABLY.

If they didn't have to, believe, they wouldn't have. That's a lot of R&D that could have gone to executive Christmas bonuses, if they could just "turn up the boost" to squeeze out 15hp.